The setup ist simple: PC with single Windows 7 Pro x64 instalation.
then...
It is one and the same PC but with different operating systems.
The above 2 statement are a little confusing. Are you dual booted on the PC where it does not work?
Is "octaneplugin.log" being generated in the Poser temp folder? If not, then the plugin is not even starting - since the first line of the plugin generates this file. If there is no octaneplugin.log, then it is NOT a Cuda issue (since the log file will report this) - but it is a Poser installation issue.
Is it possible you have installed the 32 bit version of the plugin on your 64 bit PC?
I have a chamber experiment. All pyc-files have been moved except __Init__.pyc. Then I checked what the error has reported the Phyton.
There is an issue with the PoserPython plugin system - where if there is an error in __Init__.pyc, the actual error message is not displayed. So the plugin will send the error to octaneplugin.log.
If you UNINSTALL the plugin, what does Poser -> Window -> Addons report? Can you run the "Python Shell" addon?
Paul